bsd man page for vhangup

VHANGUP(2)							System Calls Manual							VHANGUP(2)

NAME
       vhangup - virtually ``hangup'' the current control terminal

SYNOPSIS
       vhangup()

DESCRIPTION
       Vhangup is used by the initialization process init(8) (among others) to arrange that users are given "clean"' terminals at login, by revok-
       ing access of the previous users' processes to the terminal.  To effect this, vhangup searches the system tables for references to the con-
       trol  terminal  of  the	invoking process, revoking access permissions on each instance of the terminal that it finds.  Further attempts to
       access the terminal by the affected processes will yield i/o errors (EBADF).  Finally, a hangup signal (SIGHUP)	is  sent  to  the  process
       group of the control terminal.

SEE ALSO
       init (8)

BUGS
       Access to the control terminal via /dev/tty is still possible.

       This call should be replaced by an automatic mechanism that takes place on process exit.

4th Berkeley Distribution					   June 30, 1985							VHANGUP(2)